Introduction to Physical Signal Models

This book is about techniques for building real-time
computational physical models of musical instruments and audio
effects. So, why would anyone want to do this, and what exactly is a
``computational physical model''?

There are several reasons one might prefer a computational model in place of
its real-world counterpart:

A virtual musical instrument (or audio effect) is
typically much less expensive than the corresponding real instrument
(effect). Consider, for example, the relative expense of a piano
versus its simulation in software. (We discuss real-time piano
modeling in §9.4.)

Different instruments can share common controllers (such as
keyboards, wheels, pedals, etc.). Any number of virtual instruments
and/or effects can be quickly loaded as ``presets''.

Sound quality (``signal to noise ratio'') can far exceed what is
possible with a recording. This is because we can use any number of
bits per sample, rendering the ``noise floor'' completely inaudible
at all times.

Software implementations are exactly repeatable. They never need
to be ``tuned'' or ``calibrated'' like real-world devices.

It is useful to be able to ``archive'' and periodically revive
rare or obsolete devices in virtual form.

The future evolution of virtual devices is less constrained than
that of real devices.